The present invention relates to a molding machine, particularly of the centrifugal type, for low-melting materials, synthetic materials or the like.
Automatic or semiautomatic machines for centrifugal molding for low-melting metals or synthetic materials are known. Use of these machines entails a diversification in production that always requires the changing of the mold which is used. It is thus necessary to vary the molding parameters, such as for example the mold closing pressure, the centrifugation rate, the centrifugation time and the amount of material, in order to adapt them to the type of the mold.
In semiautomatic machines, in which the material to be molded is fed manually, dosage of the material is entrusted to the operator, who also sets the other molding parameters by manually adjusting potentiometers, timers and pressure regulators, which are located on the control panel of the machine.
Automatic machines, in which the material is automatically fed to the mold, are sometimes driven by programmable logic controllers, commonly known as PLCs, which however only store the machine cycle. Even in these automatic machines, some of the molding parameters, such as for example the centrifugation rate and the mold closing pressure, do not involve the PLC and must be in any case adjusted directly by the operator. The centrifugation time and the pouring time, while being handled by the PLC, are also adjusted by the operator.
Automation of these machines by means of programmable logic controllers, whilst allowing rapid changes in production by varying the molding parameters, has nonetheless failed to fully solve the problems linked to production changes. Alteration of the molding parameters is in fact entrusted to the operator himself, who must also prepare the molds, arrange them on the machine, remove the used molds from the machine and remove the formed parts from the molds.
Alteration of the molding parameters, which can be required even after the filling of a single mold, thus turns out to be a critical operation, since it can cause defective production runs due to incorrect setting of the molding parameters with reference to the mold being used.
This problem increases as the number of required production changes rises, as occurs for example in the machines used to produce costume-jewellery items or small parts made of metal with low-melting alloys, or made of polyester- or polyurethane-based resins, epoxy resins or other synthetic materials, which require considerable diversification of production, for example to follow the trends of fashion.